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Cummins SPN 5484 FMI 0: Meaning, Causes & Fix

Aftertreatment DPF Auto Regeneration Not Achieved — automatic DPF regeneration has failed to complete after multiple attempts

Reviewed by ASE Certified Mechanics · Last updated July 08, 2026

Quick Answer

SPN 5484 FMI 0 = DPF Auto Regen Failed
Severity: 🟡 CHECK SOON · System: DPF Regeneration System · ✅ Can continue with caution

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Diagnostic Reference

Field Details
Code SPN 5484 FMI 0
Protocol J1939 SPN: 5484
Component DPF Regeneration System
Manufacturer Cummins
Engine Series ISX15
Severity 🟡 CHECK SOON
SAE Reference SAE J1939-73 Digital Annex — SPN 5484, FMI 0

Possible Causes

  1. Exhaust temperature too low for regen
  2. Fuel doser valve malfunction
  3. Incomplete driving cycle for auto-regen
  4. EGR system fault increasing soot output
  5. DPF ash overload

Diagnostic & Repair Procedure

  1. Step 1: Perform parked regeneration manually using INSITE or dash switch
  2. Step 2: Check fuel doser valve for proper operation during regen
  3. Step 3: Verify exhaust temperature sensors read correctly
  4. Step 4: Check EGR system for faults increasing soot output
  5. Step 5: If parked regen also fails, DPF may need professional cleaning

Frequently Asked Questions

Is this a false alarm or a real problem?

CHECK SOON codes are rarely false alarms. The ECM has detected a parameter outside normal operating range. Sensor malfunctions can sometimes trigger false readings, but the majority of CHECK SOON codes indicate a developing issue that will worsen if left unaddressed. Use a diagnostic scan tool to verify sensor readings before replacing expensive parts.

Can I diagnose this without a scan tool?

Basic visual inspection can be performed without a scan tool — check wiring harnesses for chafing, connectors for corrosion, and related components for physical damage. However, to verify the fault, view live sensor data, and confirm the repair, a heavy-duty diagnostic scan tool (or a compatible OBD-II adapter with J1939/J1708 support) is strongly recommended for accurate diagnosis.

How soon should I schedule service?

Schedule service within the next 1–3 operating days. While the vehicle can continue operating normally, delaying repair increases the risk of the fault escalating to CHECK NEXT STOP severity. Additionally, some CHECK SOON conditions are precursors to emissions system faults that will trigger a mandatory derate if not addressed in a timely manner.

Estimated Repair Cost

Typical repair: $100–800 (Parts: $50–500 + Labor: 1–3 hours) · Costs vary by make/model and location

Diesel Repair Cost & Downtime Estimator

Enter estimated labor hours to calculate repair cost and potential fleet downtime losses. Based on national average diesel shop rate of $150/hr and daily revenue loss of $800/day for a parked truck.

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SPN 639 FMI 9 🔴 STOP ENGINE
J1939 CAN Bus Communication Loss
SPN 1322 FMI 31 🟡 CHECK AT NEXT STOP
Misfire Detected on Cylinder 6
MID 128 SID 1 FMI 5 🟡 CHECK AT NEXT STOP
Injector Cylinder 1 Circuit

Associated Symptoms

Dpf Warning Loss Of Power

References & Further Reading

Data Provenance: This fault code definition is derived from SAE J1939 standards. SPN 5484 FMI 0 is defined in SAE J1939-73 Digital Annex. Diagnostic procedures sourced from Cummins OEM technical service documentation. Not for safety-critical decisions. Consult a certified diesel mechanic before performing any repair. See our full disclaimer.